000
AXPZ20 KNHC 051604
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 05 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.

...ITCZ...

THE ITCZ AXIS WAS ANALYZED ALONG 05N77W TO 10N110W TO 09N115W 
08N130W. SCATTERED MODERATE ISOLATED STRONG WITHIN 60 NM EITHER 
SIDE OF AXIS FROM 85W TO 89W.

...DISCUSSION...

AN UPPER LEVEL RIDGE EXTENDS FROM CENTRAL MEXICO THROUGH 10N135W 
IS SHIFT EAST AND WEAKENING AHEAD OF A DEEP LAYER TROUGH DIGGING 
SE INTO THE AREA FROM THE PACIFIC WATERS NE OF HAWAII. THE 
TROUGH EXTENDS FROM NORTHERN CALIFORNIA TO 27N140W. RIDGING WILL 
BUILD BEHIND THE TROUGH AS IT PUSHES EAST INTO THE NORTHERN 
PORTIONS OF THE BAJA PENINSULA OVER THE NEXT COUPLE OF DAYS. THE 
NET EFFECT AT THE SURFACE WILL BE BUILDING HIGH PRES OVER AREA 
MAINLY N OF 15N AND W OF BAJA. THE IMPACT OF THIS RIDGE IS 
ALREADY NOTED ON OVERLAPPING SCATTEROMETER PASS SHOWING A BROAD 
AREA OF 20 TO 25 KT TRADES N OF THE ITCZ TO 20N MAINLY W OF 
135W. FURTHER SOUTH...SW CROSS-EQUATORIAL FLOW OF 15 TO 20 KT IS 
NOTED ON A 13Z QUIKSCAT PASS BETWEEN 100W AND 115W. THIS WILL 
LIKELY INCREASE CONVECTION ALONG THE ITCZ BETWEEN 100W AND 115W 
LATER TODAY. THE SW CONVERGENT FLOW IS INTERACTING WITH THE NE 
TRADES N OF THE ITCZ TO SPAWN A WEAK SURFACE TROUGH NEAR 
110W...REACHING AS FAR N AS 13N PER QUIKSCAT. GLOBAL MODELS SHOW 
THIS TROUGH WILL PERSIST OVER THE NEXT COUPLE OF DAYS AS IT 
SLOWLY DRIFTS WEST. THIS WILL INTERACT WITH THE SURFACE HIGH 
PRES TO THE NORTH AND INCREASE NE TRADE WIND FLOW TO NEAR 20 KT 
IN A BAND FROM 13N TO 22N. 

A JASON ALTIMETER PASS FROM 0830Z CORROBORATED WAVEWATCH 
GUIDANCE SHOWING SEAS TO 9 FT...LIKELY IN PRIMARILY N SWELL...IN 
AN AREA N OF 18N BETWEEN 115W AND 125W. WAVEWATCH IS ALSO 
SHOWING AN AREA OF SEAS TO 8 FT IN THE AREA OF FRESH TO STRONG 
TRADES N OF THE ITCZ TO 20N MAINLY W OF 135W. WAVEWATCH AND 
FNMOC WAVE MODELS BOTH SHOW THESE AREAS OF SWELL DECAYING BELOW 
8 FT OVER THE NEXT COUPLE OF DAYS BEFORE THE TRADES INCREASE 
AGAIN IN THE WAKE OF THE TROUGH PASSAGE.

$$
CHRISTENSEN